1. Field of the Invention
The present invention relates to an endoscope apparatus including a first optical system for observing an inside of an object and a second optical system for observing the inside of the object, the second optical system providing parallax relative to the first optical system, inside an insertion portion of an endoscope.
2. Description of the Related Art
As is well known, endoscopes are widely used in a medical field and an industrial field. In the case of endoscopes used in the medical field, an elongated insertion portion is inserted to the inside of a body cavity, which is a subject, enabling observation of an organ inside the body cavity and, as necessary, provision of various treatments using a treatment instrument inserted into a treatment instrument insertion channel.
In the case of endoscopes used in the industrial field, an elongated insertion portion is inserted to, e.g., the inside of a jet engine, a piping of a plant or the inside of a machine, which is an object, enabling, e.g., observation and/or various treatments of, e.g., damage and corrosion inside the object.
Also, the configuration in which an image pickup unit that includes an image pickup device including, e.g., an observation optical system and a CCD is provided inside a distal end portion positioned on the distal end side in an insertion direction (hereinafter simply referred to as “distal end side”) of an insertion portion of an endoscope is known.
Here, for example, in observation of the inside of an object using an industrial endoscope, as a technique that quantitatively measures an observed site such as a damage, a defect or a failed part inside a machine, what is called stereoscopic measurement in which an image of a same site is picked up in two directions that provide parallax, a correlative operation of the two picked-up still images exhibiting parallax is performed to obtain an amount of displacement of a measurement point in each of the images, and, e.g., a size and/or a depth of the observed site is quantitatively measured from the displacement amounts using the known principle of triangulation is publicly known.
For example, Japanese Patent No. 4750175 discloses a configuration of a stereoscopic observation apparatus in which in a distal end portion of an insertion portion, a first optical system and a second optical system providing parallax relative to the first optical system are provided side by side, an image pickup device is provided on the rear side of the first optical system and the second optical system in an insertion direction (hereinafter simply referred to as “rear side”), a light-blocking shutter, which serves as time-difference optical path dividing/switching means for allowing a first light flux passed through the first optical system and a second light flux passed through the second optical system to individually enter an entire light-receiving surface of the image pickup device with a time difference is provided between the first and second optical systems and the image pickup device in the insertion direction, e.g., a size and/or a depth of an observed site is measured with high accuracy using a first image of the observed site formed on the entire light-receiving surface via the first optical system and a second image of the observed site formed on the entire light-receiving surface via the second optical system with a time difference from the first image, the time difference being provided by the light-blocking shutter, the second image exhibiting parallax relative to the first image.